<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../jquery-1.7.2.js"></script>
</head>
<body>
<style>
    .a, .b {
        width: 300px;
        height: 300px;
        display: block;
        color: #333333;
    }
</style>
<div class="a">123</div>
<div class="b">123456789</div>
<script>
$(function(){
    var   num_s = "1232134456.546 ";
    var display = parseFloat(num_s).toLocaleString();
    $('.a').html(display)
})
</script>

<!--方法2-->
<script type="text/javascript">
    // 小数点位不限制
    function format_number(nStr ){
        nStr += '';
        x = nStr.split('.');
        x1 = x[0];
        x2 = x.length > 1 ? '.' + x[1] : '';
        var rgx = /(\d+)(\d{3})/;
        while (rgx.test(x1)) {
            x1 = x1.replace(rgx, '$1' + ',' + '$2');
        }
        return x1 + x2;
    }

    var a="53669988.000";
    $('.b').html(format_number(a));
</script>

</body>
</html>